12
51801210406
Specifications are subject to change without notice.
Step 3 — Start--Up Adjustments
Complete the required procedures given in the Pre--Start--Up
section before starting the unit. Do not jumper any safety devices
when operating the unit. Do not operate the unit in cooling mode
when the outdoor temperature is below 40
_
F (4
_
C) (unless
accessory low--ambient kit is installed).
IMPORTANT
: Three--phase, scroll compressors are direction
oriented. Unit must be checked to ensure proper compressor
3--phase power lead orientation. If not corrected within 5 minutes,
the internal protector will shut off the compressor. The 3--phase
power leads to the unit must be reversed to correct rotation. When
turning backwards, the difference between compressor suction and
discharge pressures may be near zero.
Checking and Adjusting Refrigerant Charge
EXPLOSION HAZARD
Failure to follow this warning could
result in death, serious personal injury,
and/or property damage.
Never use air or gases containing
oxygen for leak testing or operating
refrigerant compressors. Pressurized
mixtures of air or gases containing
oxygen can lead to an explosion.
!
WARNING
The refrigerant system is fully charged with R--410A refrigerant
and is tested and factory sealed.
NOTE
:
Adjustment of the refrigerant charge is not required
unless the unit is suspected of not having the proper R--410A
charge.
A subcooling charging chart is attached to the inside of the
compressor access panel. The chart includes the required liquid line
temperature at given discharge line pressures and outdoor ambient
temperatures.
An accurate thermocouple-- or thermistor--type thermometer, and a
gauge manifold are required when using the subcooling charging
method for evaluating the unit charge. Do not use mercury or small
dial--type thermometers because they are not adequate for this type
of measurement.
NOTE
: Allow system to operate on high stage cooling for a
minimum of 15 minutes before checking or adjusting refrigerant
charge.
IMPORTANT
: When evaluating the refrigerant charge, an
indicated adjustment to the specified factory charge must always be
very minimal. If a substantial adjustment is indicated, an abnormal
condition exists somewhere in the cooling system, such as
insufficient airflow across either coil or both coils.
1. Remove caps from low-- and high--pressure service fittings.
2. Using hoses with valve core depressors, attach low-- and
high--pressure gauge hoses to low-- and high--pressure
service fittings, respectively.
3. Start unit and let run until system pressures stabilize.
4. Measure and record the following:
a.
Outdoor ambient--air temperature (
F [
C] db).
b.
Liquid line temperature (
F [
C]) at TXV.
c.
Discharge (high--side) pressure (psig).
d.
Suction (low--side) pressure (psig) (for reference
only).
5. Using Cooling Charging Charts (See Fig. 18) compare
outdoor--air temperature (
F [
C] db) with the discharge line
pressure (psig) to determine desired system operating liquid
line temperature (See Fig. 18).
6. Compare actual liquid line temperature with desired liquid
line temperature. Using a tolerance of
2
F (
1.1
C), add
refrigerant if actual temperature is more than 2
F (1.1
C)
higher than proper liquid line temperature, or remove
refrigerant if actual temperature is more than 2
F (1.1
C)
lower than required liquid line temperature.
NOTE
:
If the problem causing the inaccurate readings is a
refrigerant leak, refer to Check for Refrigerant Leaks section.
Indoor Airflow and Airflow Adjustments
UNIT OPERATION HAZARD
Failure to follow this caution may result in unit damage.
For cooling operation, the recommended airflow is 350 to
450 cfm for each 12,000 Btuh of rated cooling capacity. For
heating operation, the airflow must produce a temperature
rise that falls within the range stamped on the unit rating
plate.
!
CAUTION
NOTE
: Be sure that all supply--air and return--air grilles are open,
free from obstructions, and adjusted properly.
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Disconnect electrical power to the unit and install lockout
tag before changing blower speed.
!
WARNING
This unit has independent fan speeds for low stage cooling and
high stage cooling. In addition, 208/230 VAC models have the
field--selectable capability to run an enhanced dehumidification
(’DEHUM’) speed on high stage cooling (as low as 320 CFM per
ton). Coupled with the improved dehumidification associated with
low stage cooling, the DHUM speed allows for a complete
dehumidification solution independent of cooling stage.
Units with the Advanced Dehumidification FIOP feature
independent normal and dehumidification fan speeds for low stage
cooling and high stage cooling.
Table 3 shows the operation modes and the associated fan speeds
with
each
mode
for
all
models
without
Advanced
Dehumidification:
Table 3 – Operation Modes and Fan Speeds
208/230 VAC Models
without Advanced Dehumidification
(AD) FIOP
Operation Mode
Fan Speed Tap
Connection
Low Stage Cooling/Heat Pump
LOW
High Stage Cooling/Heat Pump
HIGH
High Stage Enhanced
Dehumidification Cooling
DH
Continuous Fan
LOW
460 VAC Models
Operation Mode
Fan Speed Tap
Connection
Low Stage Cooling/Heat Pump
LOW
High Stage Cooling/Heat Pump
HIGH
Continuous Fan
LOW
PHR5
